Medical device

ABSTRACT

A medical device such as a syringe ( 10 ) includes a retractable needle ( 20 ) and a tilting system ( 52 ). A tilting system ( 52 ) includes a deflector in the form of a ramp ( 83 ) for deflecting legs ( 66 ) of a needle retainer ( 18 ) of the device away from a longitudinal axis ( 90 ) thereof.

The present invention relates to a medical device, such as to a syringe,catheter or cannulas having a sharp device such as a needle. The medicaldevice may be any medical device having a sharp device, such as a needleor knife. The invention relates, for example, to butterflies and mayhave application to infusion and transfusion sets and drips in which itis desirable to connect/disconnect to two or more medical devices, oneincluding a sharp device such as a needle thereon.

To avoid undesirable needle stick injuries potentially involving theundesirable transfer of media through needles, attempts have been madeto provide medical sharp devices such as safety syringes which areusable only once.

A known medical devise is disclosed in WO02/26295 A2, the content ofwhich is hereby incorporated by reference. This known medical device hasa medical sharp device, a retainer for retaining the sharp device and amoveable retractor adapted for connection with a connection member ofthe retainer and for moving the sharp device from a use position to aretracted position thereof, wherein a tilt system is provided fortilting the sharp device upon movement of the retainer to the retractedposition. However, the tilting system, which employs asymmetricallyconfigured lugs, requires close manufacturing tolerances and has beenfound to be more difficult than is desirable to manufacture forconsistently reliable operation thereof.

In U.S. Pat. No. 5,104,378, a retraction probe is a taper fit in aso-called locking bore. The locking bore is sealed off by a plungergasket front face having a so-called locating concavity. Due to thetaper fit, which requires a low 2° taper angle, the probe is relativelylong. This means the syringe barrel has to be excessively long for fluiddrawback purposes since a substantial amount of air has to be expelledafter fluid drawback. The closed front of the plunger gasket front face,it is believed, is intended to prevent oily or otherwise slippery fluidsin the syringe from stopping the taper fit of probe into locking borefrom working. The gasket front face has to be pierced by the probeduring injection, possibly causing pain to the patient and air can beforced by the volume of the probe from behind the pierced gasket frontface to the front side thereof whereby it may dangerously be injectedinto a patient.

In EP-A-0636381 a single lug is provided with a locking element, anotherlug operating as a guide causing a needle to be tilted as it iswithdrawn inside syringe. The single locking element is considered to belikely to be weak and tilting may not be consistent.

In U.S. Pat. No. 5,328,484 a needle holder has four legs which have endson four sides of a central axis of the syringe. One of the legs isengaged by a half-cone hook for tilting. The needle holder iscomplicated to make with the four legs that appear to be required tocause tilted whatever angle the needle is rotationally positioned inabout the longitudinal axis of the syringe.

In U.S. Pat. No. 5,378,240 a single catch on a needle mount engagesbehind a radial flange. Similar problems to those of EP-A-0636381 arelikely.

The present invention aims to provide an improved medical device and toaddress at least to a certain extent the problems of the prior art.

According to one aspect of the present invention, a medical device hasthe features as set out in claim 1. Another aspect is set out in claim30. Various optional features are mentioned in the dependant claims.

The deflector on the retractor enables positive deflection of theretainer. The deflector, when deflecting the retainer is preferablyspaced from a pivot region of the retainer along a longitudinal axis ofthe medical device. This spacing and the positive deflection forceenable a reliable and effective torque to be provided for tiltingpurposes.

Preferably, the medical sharp device comprises a needle, such as ahypodermic needle,

The medical device may comprise a syringe, the retractor being formed ona plunger of the syringe. The syringe may have a cylindrical barrel, ashoulder formed at one end thereof and a cylindrical neck formed on theshoulder.

Preferably, the retainer is located in the neck and a hub is providedfor preventing forward movement of the retainer out of the neck.

The medical device is preferably generally elongated in shape having afront end from which the medical sharp device in one configurationthereof extends forwards, and a rear end.

The retainer may include a medical sharp device retaining portion. Theretaining portion may be cylindrical in shape. When the medical devicecomprises a syringe having a neck, the retaining portion is preferablycylindrical, fitting snugly inside the neck in one configurationthereof.

Preferably, the connection member comprises a flexible leg. Morepreferably, two said flexible legs are provided. The flexible legs arepreferably formed in a diamond shape.

Preferably, each flexible leg is joined at one end to a sharp deviceretaining portion of the retainer and at the other distal end thereof tothe other flexible leg.

Preferably, the distal ends form a curved apex. The curved apex may beadapted to engage the deflector during connection of the retractor tothe retainer. The curved apex may be curved in two or more differentdirections. The curved apex may be domed. Curved surfaces areadvantageous in this regard in that they enable the curved apex and legsto smoothly ride over the deflector.

Preferably, the joined distal end forms an apex which is located on alongitudinal axis of the medical device. The deflector is preferablypositioned to engage the apex and thus move the apex away from thelongitudinal axis of the device. Preferably the apex is curved.

Preferably, at least one said leg includes a stop part adapted toreleasably abut against a retainer surface inside a main body of thedevice. The main body of the device may, in the case of a syringe,comprise a barrel of the syringe.

The stop part may comprise a ledge and the retainer surface may comprisean annular recess located in the main body.

Preferably, at least one leg includes a formation adapted to lock withthe moveable retractor. The formation preferably comprises a ledge.

Preferably, the retractor has a catch for engaging the formation. Thecatch and/or ledge when provided allow a very positive locking of the atleast one leg and the retractor.

Preferably, the retractor has an entrance having an entrance ledge toengage the formation.

Preferably, the deflector comprises an abutment, preferably for guidingthe leg away from a longitudinal axis of the device.

Preferably, the abutment comprises a ramp. The ramp is preferably spacedalong a longitudinal axis of the medical device from the catch. Thisenables effective and reliable deflection of the connection member fortilting purposes.

Preferably, the ramp is inclined at an angle of about 70 degrees to alongitudinal axis of the medical device. The ramp may, for example, beinclined at between 30 and 80 degrees to a longitudinal axis, 50 to 70degrees being preferred.

Preferably, the ramp is formed in an interior space of the retractor,and the ramp is preferably spaced from a rear surface of the interiorspace by a wall which is substantially parallel to the longitudinal axisof the device. Preferably, the wall is aligned with the longitudinalaxis. Thus, the apex formed by the joined distal ends of the legs mayengage the ramp and then be deflected to one side for tilting purposes,with further movement of the apex into the interior space being towardsthe rear surface thereof.

Preferably, the features of claim 19 are provided. The catch and ledgemay provide therefore a very reliable locking action.

Preferably, the features of claim 20 are provided. Thus the plunger maybefore locking of the retractor to the connection member be pushed veryclose to the front of the syringe barrel therefore allowing minimalsyringe drawback before expelling air with further forwards pressure onthe retractor causing locking to occur.

Preferably the features of claim 23 are provided. This allows insertionof the leg with the retractor and deflection of the leg withoutsubstantial frictional forces.

The present invention may be carried out in various ways and a preferredembodiment of a medical device in accordance with the present inventionwill now be described by way of example with reference to theaccompanying drawings, in which:

FIG. 1 is a partially cut away elevation of a medical device in the formof a syringe in accordance with a preferred embodiment of the presentinvention;

FIG. 2 typically shows the syringe of FIG. 1, after use, with a needlethereon in a tilted configuration;

FIG. 3 is an elevation of the needle retainer in the direction 3 of FIG.4 a;

FIG. 4 a is a partial cross-section of a barrel, needle retainer, huband sheath of the syringe of FIG. 1;

FIG. 4 b is a partial cross-section of a plunger stem and piston of thesyringe of FIG. 1;

FIG. 5 corresponds to part of FIG. 4 b, showing engagement between legsof the needle retainer and the retractor, with the needle retainer in atilted configuration; and

FIG. 6 is a schematic cross-section on the plane VI-VI in FIG. 4 b;

FIG. 7 shows a modification to the retainer (18) of FIG. 4 a;

FIG. 8 shows a further modification of the retainer (18), having onlyone leg (66); and

FIG. 9 shows a modification to the deflector to that shown in FIG. 4 b,in that a curved ramp/wall are provided.

As shown in FIGS. 1 and 2, a preferred embodiment of a medical device inthe form of a syringe (10) in accordance with the present inventioncomprises a cylindrical barrel (12), a plunger (14), a piston (16), aneedle retainer (18), a hypodermic needle (20) with a sharp tip end(22), a hub (24) and a needle sheath (26).

As shown in FIGS. 1 and 2, the barrel (12) has a main cylindrical part(28) having finger tabs (30) located at a rear end thereof and ashoulder (32) and small diameter cylindrical neck (34) formed at a frontend (36) thereof. Although the piston (16) and plunger stem (40) areshown somewhat schematically in FIG. 2, it will be appreciated that theplunger stem (40) includes frangible weakened portions (38) to assistwith snapping of the stem (40) after use, to assist in preventing theuse of the syringe (10).

In use, the syringe (10) may be presented to the user with the piston(16) spaced rearwardly of the front end (36) of the barrel cylindricalpart (28). The sheath (26) may be removed and the piston (16) may bemoved using the knob (42) towards the rear end (44) of the cylindricalmain part (28) of the barrel (12) in order to draw fluid (not shown)into the barrel (12). Air (not shown) may then be expelled from thesyringe (10) in accordance with standard procedure and the syringe maythen be used for injection purposes. Once the piston (16) reaches thefront end (36) of the main cylindrical part (28) of the barrel (12), aretractor (50) (see FIG. 4 b) formed on the front of the stem (40)engages the needle retainer (18) and the retractor (50) may then bepulled rearwardly again using the knob (42) until the tip (22) of theneedle (20) passes the neck (32) and the needle (20) is tilted by atilting system (52), formed by the retractor (50) and needle retainer(18) (see FIGS. 2 and 5). Once tilted, as shown in FIG. 2, the needlecannot be pushed forwards again through the neck (34). Additionally, thebarrel includes stops (54) for preventing the piston (16) from beingremoved rearwardly from the barrel. Thus, once used and in the tilledconfiguration, the needle (20) cannot be reused. Therefore, needle stickinjuries are desirably prevented from occurring and, furthermore, thepossibility of reuse of the syringe (10) is minimised, such that theneedle (20) is not used for procedures on more than one human or animaland the risk of the transfer of undesirable materials between the sameis minimised.

It will be appreciated that, as well as being useable for injectionpurposes, the syringe (10) may be used for withdrawing samples, such asblood or other fluids from humans or animals or for other purposes.

With reference to FIG. 4 a and FIG. 3, the needle retainer (18) includesa cylindrical portion (60) which sits snugly inside the neck (34). Thecylindrical portion includes a through-bore (62) into which the needle(20) is a press fit to a position in which a rear end (not shown) of theneedle (20) is located at a rear end (64) of the through-bore (62). Inother embodiments, the rear end of the needle may be located in front ofor to the rear of the rear end (64) of the bore (62) as described. Twoflexible legs (66) are attached at front ends (68) thereof to thecylindrical portion (60) of the needle retainer (18). As shown in FIG. 4a, the flexible legs (66) form a diamond shape and are joined at distalends (70) thereof to form a curved apex (72), which is domed. Each leg(66) includes a flat ledge (74) which is in the use configuration ofFIG. 4 a engaged with an annular ledge (76) at a rear end (78) of aninternal bore (80) of neck (34).

As the plunger (16) is moved forwards, the annular ledges (82) of theretractor (50) engage against rear wedging surfaces (84) of the legs(66), resiliently wedging and pushing the legs (66) together so that theledges (74) disengage from the annular ledge (76). Furthermore, ledges(86) on the legs (66) engage behind annular ledges (82) of the retractor(50) and the curved apex (72) engages an internal ramp (88) of theretractor (50) and is resiliently pushed to one side of the longitudinalaxis (90) of the syringe (10) and is then prevented from returning tothe longitudinal axis (90) by a substantially vertical wall (92) of theretractor (50). The legs (66) are therefore essentially bent to one sideby the retractor in the example, with the cylindrical portion (60)remaining in line with the axis (90) to the left of the position shownin FIG. 4 a by the retractor (50). As the needle tip (22) passes theneck (34) and shoulder 32, the legs (66) adopts the configuration shownin FIG. 2. The cylindrical portion (60) of the needle retainer (18) istilted (sec FIG. 5) with respect to the longitudinal axis of the syringe(10), with at least one of the ledges (86) engaged with at least one ofthe ledges (82), and with the apex (72) formed by the joined distal endsof the legs (66) located to the side of the substantially vertical wall(92), by which the apex (72) is retained away from the axis (90).

FIG. 5 shows only one engaged configuration of the legs (66) onceretained by the retractor (50). If the legs (66) engage the retractor(50) when in another location or configuration, such as when the legsare located in a position rotated at 90 degrees or any other anglearound the longitudinal axis from that shown in FIGS. 4 a and 5, suchthat the engagement with the ramp (88) is different, the apex and legswill still be deflected by the ramp (88) and then held to the side ofthe axis (90) by the wall (92) due to the configuration of the legs (66)(with their apex initially on the central axis (90)), ramp (88) and wall(92). The apex is preferably curved in two directions as shown by dottedline 720 as a modification in FIG. 3 (the curve in the other directionbeing as in FIG. 4 a. Thus, the apex is preferably domed.

The ramp (88) is inclined at an angle A (see FIG. 4 b) to thelongitudinal axis (90) of the syringe (10) of 70″. The ramp is generallyflat but may be curved. The wall (92) is also generally flat but may becurved in some other embodiments.

It will be seen that the ledges (82) of the retractor (50) are spacedapart by gaps (94). These gaps (94) provide some resilience for theretractor (50) to facilitate the engagement with the legs (66).

The retractor (50) may be formed integrally with or separately from thestem (40). Preferably, these parts are formed integrally. Thus, it willbe seen that the syringe (10) may have a particularly simpleconstruction consisting of only seven parts to be assembled together,namely the sheath (26), hub (24), needle retainer (18), needle (20),barrel (12), stem (40)/retractor (50) and piston (16).

The deflector of the tilting system (52) formed by the configuration ofthe abutment ramp (88), wall (92) and legs (66) has been found to beparticularly reliable and effective in practice. The use of the twoflexible legs joined at the distal ends thereof provides a firmengagement with the interior ledge (76) of the neck (34). Despite thiseffective resilience, the legs (66) may be reliably squeezed together bythe retractor (50) for disengagement from the ledge (76) and the needle(20) may then be reliably retracted into the syringe (10) and tilted inorder to minimise the possibility of reuse. The ramp (88) and wall (92)are spaced longitudinally from a pivot region (100) of the retainer (18)and/or of retractor, namely from the region of the formations (86,74)and/or the entrance ledges (82) of the retractor, and this spacedconfiguration allows a reliable torque to be applied to the retainer(18) for tilting.

FIG. 7 shows a modification to the needle retainer (18) in which twolegs (66) have distal ends (70) having a curved formation or ball (110)formed thereon. The end (70) of the legs (66) and the ball (110) arelocated on the central axis (90) of the needle retainer (18) and medicaldevice. The central nature of the ball (110) and the way in which theromp/wall (88/92), extend across the axis (90) ensure that the needle(20) is tilted reliably.

FIG. 8 shows a modification in which the needle retainer (18) only hasone leg (66) having a distal end (70) which has a curved formation orball like element (110) located thereon, the curved element or ballbeing located on the central axis (90) of the needle retainer (18) upperportion (19) and/or of the medical device. Although only one leg (66) ispresent, the location of the end (70) thereof on the central axis (90)and the configuration of the ramp (88) and wall (92) ensure that thetilting of the needle (20) is reliable.

As shown in FIG. 9, the abutment may comprise a curved ramp/wall (88/92)of increasing steepness across the a retractor (50) from one side (51)to another side (53) thereof. As in the embodiments shown in FIG. 4 b,the ramp/wall (88/92) extend across to the longitudinal axis (90) orslightly further than the central axis from the side (51).

In the embodiment of FIG. 4 b, the top (89) of the ramp (88) is locatedat a distance 1.1 mm above 2 lower surface (93) of the interior of theretractor (50). The distance from the lower surface (93) to uppersurfaces (83) of ledges (82) is 3 mm. The distance between uppersurfaces (83) of the ledges (82) and lower surfaces (85) of the ledges(82) is 0.5 mm. An interior cross dimension or diameter between facingsurfaces (87) of the ledges (82) is 1.7 mm and an interior crossdimension or diameter of the retractor (50) between opposing interiorside walls (91) of the retractor is about 2-2.3 mm. preferably, theheight of the deflector to the point (89) from a lower surface (93) ofthe inside of the retractor (50) is about 30%-40% of the height of theinterior of the retractor from the lower surface (93) to upper surfaces(83) thereof. This height of the deflector may be about 40%-60% of across dimension or diameter of the retractor between interior side walls(91) thereof. The ramp (88) and wall (92) may be flat, as in FIG. 4 b.Alternatively, it may be curved in one or two directions. A curvedramp/wall (88/92) are shown in FIG. 9, this deflector being curved inonly one dimension and extending consistently across the retractor asshown by the nature of the cross section in FIG. 9.

The deflector/leg configurations in the various embodiments allow thetilting of the needle (20) to work reliably in any rotationalconfiguration of the needle (20) and retainer (18) about thelongitudinal axis (90) relative to the deflector (88, 92). Inparticular, this reliability is aided by the way in which the deflectorextends to or slightly across the central axis (90) and in that distalend (70)/domed ends (72,110) of leg(s) are located on or near to thecentral axis (90) in the use configuration of the needle (20). Theembodiment of FIG. 8 may be farther modified by replacing the off centreleg (66) with a single central leg (66)—having the curved end (110) asshown in FIG. 8 in dashed lines.

Furthermore, before the ledges 86 have engaged the retractor catch, theretractor may be freely pushed up to engage the surfaces 84 withoutlocking, so that liquid or other material can then be freely drawn backwith a minimum further air expulsion step then being needed. This ispossible since the legs can enter locking cavity 251 of retractor freelywithout locking thereto and without disengaging from ledge (76). Onlyupon fill insertion of the legs 70,72 do the legs lock to the retractor.

As shown in FIG. 5, the legs 70,72, or at least the distal ends thereofare deflected by ramp 88 into open side cavity 253 of locking chamber251, the side cavity allowing this deflection with minimal frictionforces.

Various modifications may be made to the specific embodiment describedwithout departing from the scope of the invention as defined by theclaims as interpreted under patent law.

1. A medical device having a medical sharp device, a retainer forretaining the sharp device and a movable retractor adopted forconnection with a connection member of the retainer and for moving thesharp device from a use position to a more retracted position thereof,wherein a tilt system is provided for tilting the sharp device uponmovement of the sharp device to the more retracted position thereof, thetilt system including a deflector on the retractor for deflecting theconnection member during movement of the retractor into engagement withthe retainer, the connection member having an engagement part thereof ona longitudinal axis, the engagement part being deflected off the axis bythe deflector.
 2. A medical device as claimed in claim 1 in which themedical sharp device comprises a needle.
 3. A medical device as claimedin claim 1 which comprises a syringe, the retractor being formed on aplunger of the syringe.
 4. A medical device as claimed in claim 3 inwhich the syringe has a cylindrical barrel, a shoulder formed at one endthereof and a cylindrical neck formed on the shoulder.
 5. A medicaldevice as claimed in claim 4 in which the retainer is located in theneck, and in which a hub is provided for preventing forward movement ofthe retainer out of the neck.
 6. A medical device as claimed in claim 1in which the retainer includes a cylindrical sharp device retainingportion.
 7. A medical device as claimed in claim 1 in which theconnection member has one end connected to a sharp retaining portion ofthe retainer and another, distal end thereof located on a longitudinalaxis of the medical device in one configuration thereof.
 8. A medicaldevice as claimed in claim 7 in which the distal end of the connectionmember engages the deflector.
 9. A medical device as claimed in claim 1in which the connection member comprises a flexible leg.
 10. A medicaldevice as claimed in claim 9 in which two said flexible legs areprovided, preferably formed in a diamond shape.
 11. A medical device asclaimed in claim 10 in which each flexible leg is joined at one endthereof to a sharp retaining portion of the retainer and at the other,distal end thereof to the other flexible leg.
 12. A medical device asclaimed in claim 7 in which a curved (preferably domed) nose is formedon the distal end of at least one connection member.
 13. A medicaldevice as claimed in claim 11 in which the joined distal ends form anapex which is located on a longitudinal axis of the medical device inone configuration thereof.
 14. A medical device as claimed in claim 13in which the apex is domed.
 15. A medical device as claimed in claim 9in which at least one leg includes a stop part adapted to releasablyabut against a retainer surface inside a main body of the medicaldevice.
 16. A medical device as claimed in claim 15 in which the stoppart comprises a ledge and in which the retainer surface comprises anannular recess located in the main body.
 17. A medical device as claimedin claim 9 in which at least one leg includes a formation adapted tolock with the moveable retractor.
 18. A medical device as claimed inclaim 17 in which the formation comprises a ledge.
 19. A medical deviceas claimed in claim 18 in which the retractor has a catch for positivelylocking with the ledge, preferably with generally planar abutment facesof the catch and ledge abutting one another.
 20. A medical device asclaimed in claim 17 in which the retractor has a locking cavity and theat least one leg is freely insertable and removable from said cavity inintermediate positions of the leg relative to the cavity and in whichthe leg and cavity are configured such that the locking of the leg tothe retractor occurs upon a full insertion of the leg into the cavity.21. A medical device as claimed in claim 17 in which the retractor hasan entrance having an entrance ledge adapted to engage the formation.22. A medical device as claimed in claim 9 in which the deflectorcomprises an abutment for guiding the leg away from a longitudinal axisof the medical device.
 23. A device as in claim 22 in which the abutmentis adapted to guide the leg sideways into a side chamber portion of theretractor.
 24. A medical device as claimed in claim 22 in which theabutment includes a ramp.
 25. A medical device as claimed in claim 24 inwhich the ramp is inclined at an angle of about 70 degrees to alongitudinal axis of the medical device.
 26. A medical device as claimedin claim 24 in which the ramp is formed in an interior space of theretractor, and in which the ramp is spaced from a rear surface of theinterior spaced by a wall substantially parallel to a longitudinal axisof the device.
 27. A medical device as claimed in claim 26 in which thewall is aligned with the longitudinal axis of the medical device.
 28. Amedical device as claimed in claim 22 in which the abutment extendsacross the longitudinal axis.
 29. A medical device as claimed in claim28 in which at least part of the wall is located on an opposite side ofthe longitudinal axis to at least part of the ramp.
 30. A medical devicehaving a medical sharp device, a retainer for retaining the sharp deviceand a movable retractor adapted for connection with a connection memberof the retainer and for moving the sharp device from a use position to amore retracted position thereof, wherein a tilt system is provided fortilting the sharp device upon movement of the sharp device to the moreretracted position thereof, the tilt system including a deflector on theretractor for deflecting the connection member, the connection memberhaving a portion thereof on a central axis of the retainer which engagesthe deflector and is guided away from the central axis by the deflector.